Mass production of ophthalmic lenses, in particular contact lenses such as soft contact lenses, generally includes one or more bath treatments in which the lenses are treated with water or specific treatment liquids in order to modify the properties of the lenses. For example, in the manufacture of silicone hydrogel soft contact lenses a lens-forming material is dispensed into a mold for single use or into a reusable mold and is subsequently cured to form the contact lens. After curing any undesirable substances, for example solvents, contained in the cured contact lens need to be extracted before the contact lens can be worn. In addition, it may be necessary or desirable to apply a coating to the extracted contact lens in order to increase the contact lens' hydrophilic properties. Both, the extraction process as well as the coating process, are typically performed by successively transporting the cured contact lenses through one or more baths.
In this regard, it is known to transport the contact lenses through the baths in the interior of contact lens carriers having the shape of a more or less cylindrical tube having a bottom. The tube and the bottom may comprise openings or slots through which the treatment liquid may enter and exit the interior of the tube to allow the contact lens contained in the interior of the tube to be sufficiently exposed to the treatment liquid. The contact lens is retained in the interior of such tube by means of a circular diaphragm having inwardly extending flexible fins, so that once the contact lens has been inserted into the interior of the tube in the space between the diaphragm and the bottom of the tube, the lens cannot escape from that space until it is removed again from this space, for example with the aid of a suitable gripper. A plurality of such tubes may be arranged side by side and may be transported through the baths. This is an efficient way of treating the lenses in baths, however, only if the duration of exposure of the lens to the treatment liquid or liquids is within certain time limits. In particular, for rather long exposure times as this is the case, for example, in the extraction of customized silicone hydrogel lenses in aqueous treatment baths, the efficiency of the treatment process is open to improvement.
Hence, for reasons of efficiency and cost-effectiveness there is a continuing need for contact lens carriers allowing high numbers of contact lenses to be simultaneously exposed to the treatment liquid. On the other hand, it is crucial that the contact lenses are sufficiently exposed to the treatment liquid as the treatment of the contact lenses, for example the extraction or the coating of the contact lenses, must be as effective and complete as possible. At the same time, it is necessary to ensure that the contact lenses cannot escape from their carrier during the bath treatment.